SQUATS! (legs)
Put your hands on your hips or fold them over your chest. From a standing position, feet about shoulder-width apart, squat down until both knees reach 90 degrees. As you lower yourself, keep your lower back slightly arched, head up, and stick your glutes out as if you were going to sit in a chair - Go as LOW as you can go - until knees & hips are fully bent! Once you reach the bottom position, flex through your quads, hamstrings and glutes to power yourself back up to a standing position and repeat. This can also be done with dumbbells in your hands if you have them at home.

PUSH-UP (chest)
Place your hands a little wider than your shoulders, put your toes on the floor, feet and legs together, and raise up into an arms-extended position. Slowly lower yourself until your chest just touches the floor, return to the starting position and repeat. As you lower yourself, concentrate on feeling the stretch in your chest, and flex on the way up rather than using a quick piston action to finish your set. If you're a beginner to push-ups, you can put your knees on the floor.

Or if regular push ups are too hard, you could try COUNTER PUSH-UPS!
Stand facing a sturdy table or counter arm's length away. Rest your hands on the edge, palms down, fingers forward and shoulder-width apart. Lean in, then walk your feet out in back. Lower your hips slightly so that your body forms a diagonal line. Bend your elbows and lower your chest to the counter. Look down, not forward. Tighten your abs to support your lower back. Push up by straightening your elbows and repeat 8 to 15 times.

CRUNCH (abs)
Lie faceup, your knees bent and feet on the floor. Keep your hands behind your head--avoid the temptation to pull on your head. Curl your torso as you bring your shoulder blades up a few inches, squeeze your abs, and then slowly return to the starting position. To keep the pressure on, don't spend more than a second in the "down" position; the longer your shoulder blades are off the floor, the more work your abs must do. Remember: Quality over Quanity!!! It's better to do 10 good crunches than 100 bad ones!

Back Extension (Back)
Lie facedown on the floor and place hands behind head (advanced) or fold them behind your back. Contract your lower back to lift your chest a few inches off the floor and lower back down. You can simultaneously lift legs for more intense exercise.